Multi-evaporation system

ABSTRACT

Provided is a multi-evaporation system which carries out a multi-evaporation process in an air-conditioning cycle of a vehicle air conditioning system, thereby enhancing system efficiency. The multi-evaporation system includes a compressor  10  which sucks and compresses refrigerant; a condenser  20  which condenses the refrigerant compressed in the compressor  10;  an expanding means  30  which receives the refrigerant condensed in the condenser  20  through an inlet port  31,  branches the refrigerant into at lest two or more, discharges the refrigerant through at least two or more discharging part  32   a  to  32   n,  and throttles the refrigerant before or after the refrigerant is branched; and an evaporator  40  which comprises at least two or more evaporating parts  41  to  4 N so as to receive and evaporate the refrigerant discharged from the expanding means  30  and then introduce the evaporated refrigerant into the compressor  10.

TECHNICAL FIELD

The present invention relates to a multi-evaporation system, and moreparticularly, to a multi-evaporation system which carries out amulti-evaporation process in an air-conditioning cycle of a vehicle airconditioning system, thereby enhancing system efficiency.

BACKGROUND ART

In the automobile industry, as general concerns about energy andenvironment are increased globally, the efficiency in each partincluding fuel efficiency has been steadily improved, and the externalappearance of a vehicle has been also diversified in order to satisfyvarious demands of customers. According to such a tendency, research anddevelopment on lighter weight, smaller size and multi-function of eachvehicle component has been carried out. Particularly, in anair-conditioning unit for a vehicle, since it is generally difficult tosecure an enough space in an engine room, there have been many effortsto manufacture an air-conditioning system having a small size and highefficiency.

Meanwhile, the air-conditioning system generally includes an evaporatorfor absorbing heat from a peripheral portion, a compressor forcompressing refrigerant, a condenser for radiating heat to a peripheralportion, and an expansion valve for expanding the refrigerant. In theair-conditioning system, the gaseous refrigerant introduced from theevaporator to the compressor is compressed at a high pressure and hightemperature, and the compressed gaseous refrigerant radiatesliquefaction heat to a peripheral portion while passing through thecondenser so as to be liquefied, and the liquefied refrigerant is passedthrough the expansion valve so as to be in a low pressure lowtemperature wet vapor state and then introduced again into theevaporator so as to be vaporized.

Herein, the substantial air conditioning action occurs in the evaporatorthat absorbs vaporization heat from a peripheral portion while the wetvapor refrigerant is vaporized. As described above, the condenser andevaporator in the air-conditioning system typically fall into thecategory of the heat exchanger. Therefore, the improving of evaporatorefficiency is a very important factor in the air-conditioning system.

FIG. 1 is a perspective view of a general evaporator. As shown in thedrawing, the evaporator 100 includes a pair of header-tanks 110, aplurality of tubes 120 and a plurality of fins 130. The header-tank 110includes a plurality of tube insertion holes 113 that are formed at alower surface or an upper surface thereof to be extended in a widthdirection thereof and arranged in a longitudinal direction thereof, anend cap 114 that closes both longitudinal ends thereof, at least onepartition wall 111 that partitions an inner space as a refrigerantpassage in the longitudinal direction, and at least one baffle 112 thatpartitions the refrigerant passage in the width direction. Further, bothends of the tube 120 are fixedly inserted into the tube insertion hole113 of the header-tank 10 so as to form a refrigerant passage, and thefin 130 is interposed between the tubes 120 to enhance heat exchangeperformance. Herein, the type of evaporator shown in FIG. 1 is just anexample. The tube 120 may be arranged in two rows (as shown in FIG. 1),a single row, or three rows. Further, positions and shapes of thepartition wall 111 and the baffle 112 may be changed according to adesign of the refrigerant passage, and a communicating hole may beformed in the partition wall 111. Therefore, the evaporator is notrestricted to that of FIG. 1.

There have been many efforts to increase the evaporator efficiency byvariously changing the basic construction of the evaporator shown inFIG. 1. FIG. 2 shows evaporation systems constructed by varioustechniques for improving the efficiency of the conventional evaporator.

FIG. 2A shows an evaporation system described in Japanese PatentPublication No. 2000-062452 (hereinafter, prior art 1). In the prior art1, two evaporators are arranged in parallel so that refrigerant passedthrough an expanding means is branched off and then passed through eachof the evaporators. In an embodiment shown at the right side of FIG. 2A,one of the evaporators accommodates a cold storage material andfunctions as a cold storage unit so as to increase cooling efficiency ofair passing through the evaporator. FIG. 2B shows an evaporatoremploying a technique described in Japanese Patent Publication No.2009-085569 (hereinafter, prior art 2). In the prior art 2, twoevaporators are arranged in parallel so that refrigerant passed throughan expanding means is passed through, in turn, each evaporator. And FIG.2C shows an evaporator employing another technique described in JapanesePatent Publication No. 2005-308384 (hereinafter, prior art 3). In theprior art 3, two evaporators are arranged in parallel so thatrefrigerant passed through an expanding means is passed through, inturn, an evaporator, an ejector, and an evaporator.

However, the evaporation systems described in the prior arts have someproblems as followings. In case of the prior art 1, one of the twoevaporators substantially functions as the cold storage unit, and if thecold storage unit is sufficiently cold-stored, the air is efficientlycooled. But in an initial stage that the cold storage unit is notcold-stored absolutely, the refrigerant passed through the expandingmeans absorbs from both of the air and the cold storage material, andthus the cooling efficiency of the air is deteriorated. Further, whenthe driving is intermittently performed at the side of the cold storageunit and low temperature refrigerant is stored, it is difficult tocontrol the flow thereof. Furthermore, since the prior art 1 functionsjust as the cold storage unit, the air-conditioning operation ismaintained only for a desired time period when an engine is stopped, andthus it is impossible to entirely enhance the cooling performance.

In case of the prior art 2, since the refrigerant is passed through, inturn, the two evaporators which are arranged in series, there is anadvantage in that it is possible to maximize a length of the refrigerantpassage. However, since the length of the refrigerant passage becomestoo long, the pressure drop due to the passing of the evaporators issharply increased, thereby considerably reducing the system efficiency.Further, in the structure of the prior art 2, since the refrigerant ofthe first evaporator is introduced into the second evaporator,evaporation pressure is excessively increased, thereby reducing thesystem efficiency.

In addition, in case of the prior art 3, the refrigerant is passedthrough, in turn, the evaporator, the ejector and the evaporator, and itis promoted that the ejector is used to mix the refrigerants havingdifferent temperature, thereby improving a temperature condition of therefrigerant and thus increasing the air-conditioning efficiency.However, the prior art 3 has some problems as follows. In theconstruction of the prior art 3, since the refrigerant is passedthrough, in turn, the two evaporators which are arranged in series,there is an advantage in that it is possible to maximize a length of therefrigerant passage in which heat exchange is occurred. However, sincethe length of the refrigerant passage becomes too long, the pressuredrop due to the passing of the evaporators is sharply increased, therebyconsiderably reducing the system efficiency. Further, in the structureof the prior art 3, since the refrigerant of the first evaporator isintroduced into the second evaporator, evaporation pressure isexcessively increased, thereby reducing the system efficiency.

Therefore, the study on a new evaporation system for simultaneouslyenhancing the air-conditioning efficiency and the system efficiency inthe evaporator regardless of a time and condition of the driving isrequired.

DISCLOSURE Technical Problem

An object of the present invention is to provide a multi-evaporationsystem in which multi-evaporation is occurred by a plurality ofevaporators arranged in parallel, thereby enhancing the air-conditioningand system efficiency.

Another object of the present invention is to provide amulti-evaporation system which is further provided with an ejector so asto mix the refrigerants and thus improve the temperature condition,thereby enhancing the air-conditioning and system efficiency.

Technical Solution

To achieve the object of the present invention, the present inventionprovides a multi-evaporation system including a compressor 10 whichsucks and compresses refrigerant; a condenser 20 which condenses therefrigerant compressed in the compressor 10; an expanding means 30 whichreceives the refrigerant condensed in the condenser 20 through an inletport 31, branches the refrigerant into at lest two or more, dischargesthe refrigerant through at least two or more discharging part 32 a to 32n, and throttles the refrigerant before or after the refrigerant isbranched; and an evaporator 40 which comprises at least two or moreevaporating parts 41 to 4N so as to receive and evaporate therefrigerant discharged from the expanding means 30 and then introducethe evaporated refrigerant into the compressor 10, wherein theevaporating parts 41 to 4N are parallelly disposed in a flow directionof air passing through the evaporating parts 41 to 4N so that the airblown by a single blower 60 is passed through in turn the evaporatingparts 41 to 4N so as to be cooled, and the discharging parts 32 a to 32n and the evaporating parts 41 to 4N are connected by refrigerantpassages disposed in parallel.

The refrigerant which is branched and discharged from the dischargingparts 32 a to 32 n of the expanding means 30 is supplied to theevaporating parts 41 to 4N at the same time. Further, a distributionrate of the refrigerant supplied to the evaporating parts 41 to 4Nbecomes higher as the evaporating parts 41 to 4N are disposed at a moreupstream side of the flow direction of the air blown from the blower 60.

The evaporating parts 41 to 4N are formed by dividing the evaporator 40into at least two or more evaporating regions, or the evaporating parts41 to 4N are formed by dividing the evaporator 40 into two evaporatingregions, or the evaporating parts 41 to 4N are formed separately so asto be closely contacted with each other and arranged in parallel.

The expanding means 30 comprises an inlet passage 33 which passes therefrigerant introduced from the inlet port 31; and at least two or moreoutlet passages 34 a to 34 n which are formed by dividing the inletpassage 33 into at least two or more so as to discharge the refrigerantto the discharging part 32 a to 32 n. At this time, the expanding means30 comprises an expanding part before branching 35 which is provided atthe inlet passage 33 so as to throttle the refrigerant, and an expandingpart 35 a to 35 n which is provided at the outlet passage 34 a to 34 nso as to throttle the refrigerant. And the expanding part beforebranching 35 and the expanding part 35 a to 35 n are respectivelycomprised of one selected from an expansion valve, an orifice, acapillary tube, and a reducing means.

The expanding means 30 comprises the expanding part before branching 35,and the expanding parts provided at the outlet passages except the firstoutlet passage 34 a which supplies the refrigerant to the firstevaporating part 41 disposed at an uppermost stream side of the flowdirection of the air blown by the blower 60. And the expanding partbefore branching 35 is comprised of an expansion valve, and theexpanding parts provided at the outlet passages except the first outletpassage 34 a is comprised of one selected from reducing means comprisingan orifice and a capillary tube.

The expanding means 30 is formed so that a pressure reduction value ofthe refrigerant supplied to the evaporating part disposed at thedownstream of the flow direction of the air blown by the blower 60 islarger than that of the refrigerant supplied to the evaporating partdisposed at the upstream of the air flow direction.

The expanding means 30 is formed so that a pressure reduction value ofthe refrigerant supplied to the evaporating part having a relativelysmall flow rate becomes larger.

The expanding means 30 is comprised of expanding parts 35 a to 35 nwhich are provided at the outlet passages 34 a to 34 n so as to throttlethe refrigerant, and the expanding parts 35 a to 35 n are formed so thata pressure reduction level is controlled by adjusting an opening degreethereof. At this time, the expanding means 30 is formed so that apressure reduction value of the refrigerant supplied to the evaporatingpart disposed at the downstream of the flow direction of the air blownby the blower 60 is larger than that of the refrigerant supplied to theevaporating part disposed at the upstream of the air flow direction.

The multi-evaporation system further includes an ejector which isprovided between the evaporator 40 and the compressor 10 so as to suckthe refrigerant discharged from a part or whole of the remainingevaporating parts using a flow speed of the refrigerant discharged froma part of the first to Nth evaporating parts 41 to 4N, raise pressure ofthe refrigerant and then supply the refrigerant to the compressor 10.

The ejector 50 includes a nozzle part 51 which decompresses and expandsthe refrigerant discharged from a part of the first to Nth evaporatingparts 41 to 4N, and increases a flow speed of the refrigerant; a suctionpart 52 which sucks the refrigerant discharged from part or whole of theremaining evaporating parts using an increased flow speed of therefrigerant injected from the nozzle part 51; and a diffuser part 53which mixes the refrigerant injected from the nozzle part 51 and therefrigerant sucked through the suction part 52 and then raise pressureof the mixed refrigerant.

The ejector 50 is formed so that the refrigerant has a subsonic speed.

The multi-evaporation system further includes a detecting means 70 whichis provided at passages for connecting the expanding means 30, theevaporator 40 and the compressor 10 so as to detect temperature andpressure of the refrigerant and control an operation of the expandingmeans 30.

Advantageous Effects

According to the present invention, the refrigerant that is branched inplural while passing through an expanding means is multi-evaporated bythe plurality of evaporators arranged in parallel, thereby efficientlyevaporating the refrigerant. In other words, temperature of theoverheated air is lowered while the air passes through each evaporator,and thus the expanding means that is disposed at the front end of eachevaporator expands the pressure and temperature of the refrigerantresponding to the temperature of the air introduced into each evaporator(high temperature range: an increase in the refrigerant pressure andtemperature by a small margin, low temperature range: decrease in therefrigerant pressure and temperature), and thus the control of theevaporation range is precisely carried out, thereby efficientlyachieving the evaporation. Further, in the process that the refrigerantis branched off and then passed through the evaporator, the length ofthe refrigerant passage is remarkably reduced comparing with that in theprior art, thereby improving the pressure drop of the refrigerant whenthe refrigerant is passed through the evaporator.

Further, according to the present invention, it is possible toconsiderably enhance the efficiency of the entire system. FIG. 10 showsexperiment values of comparing a system using a conventional evaporatorand a dual evaporation system having a double evaporating rangeaccording to the present invention. As an experimental result with therespect to the same component specifications at an ambient temperatureof 35° C., it can be experimentally confirmed that the systemperformance is remarkably increased in all cases, for example, 9.9% at alow speed, 12% at a high speed and 6% at an idle state.

Furthermore, since the refrigerants that is branched in plural and thenevaporated in each evaporator are mixed using the ejector, theconditions like the temperature and pressure of the refrigerant which isdischarged from the evaporator and then introduced into a compressor isoptimized to thereby further improve the system efficiency.Particularly, since the ejector used in the present invention isconstructed so that the refrigerant is flowed at a subsonic speed, therefrigerant is efficiently mixed and also noise is not generated.

DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the presentinvention will become apparent from the following description ofpreferred embodiments given in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a view showing a construction of a general evaporator.

FIG. 2 is a view of a conventional evaporation system.

FIG. 3 is a view of a multi-evaporation system in accordance with thepresent invention.

FIG. 4 is a view showing an expanding means of the multi-evaporationsystem in accordance with the present invention.

FIG. 5 is a view of the multi-evaporation system having an ejector inaccordance with the present invention.

FIG. 6 is a view of the ejector in accordance with an embodiment of thepresent invention.

FIG. 7 is a view of the expanding means in accordance with an embodimentof the present invention.

FIG. 8 is a view showing a p-h line in a refrigerating cycle device.

FIG. 9 is a view showing a pressure drop rate in the refrigerating cycledevice.

FIG. 10 is a view showing an cooling performance in each of theconventional evaporator and the evaporator of the present invention.

DETAILED DESCRIPTION OF MAIN ELEMENTS

10: compressor 11: condenser 20: expanding means 31: inlet port 32a~32n:first to Nth discharging part 33: inlet passage 34a~34n: first to Nthoutlet passage 35: expanding part before branching 35a~35n: first to Nthexpanding parts 40: evaporator 41~4N: first to Nth evaporating part 60:blower 70: detecting means

BEST MODE

Hereinafter, the embodiments of the present invention will be describedin detail with reference to accompanying drawings.

FIG. 3 is a view of a multi-evaporation system in accordance with thepresent invention. Like a general air-conditioning system, themulti-evaporation system of the present invention includes a compressor10 which sucks and compresses refrigerant; a condenser 20 whichcondenses the refrigerant compressed in the compressor 10; an expandingmeans 30 which throttles the refrigerant condensed in the condenser 20;and an evaporator 40 which evaporates the refrigerant throttled in theexpanding means 30. As shown in FIG. 3, the refrigerant discharged fromthe evaporator 40 is flowed again into the compressor 10 such that therefrigerant is circulated. The multi-evaporation system of the presentinvention has a passage for connecting the expanding means 30, theevaporator 40 and the compressor 10, and also further includes adetecting means 70 which detects temperature and pressure of therefrigerant so as to control the expanding means 30.

In the constructions of the expanding means 30 and the evaporator 40,the multi-evaporation system of the present invention has differentfeatures from the general air-conditioning system.

The expanding means 30 receives the refrigerant condensed in thecondenser 20 through an inlet part 31, and throttles and then dischargesit. Herein, as shown in FIG. 3, the expanding means 30 has refrigerantpassages branched into N, and the refrigerant is discharged throughfirst to Nth discharging parts 32 a to 32 n. The refrigerant before orafter being branched is throttled in the expanding means 30 (wherein Nis an integer equal to or larger than 2). As described above, therefrigerant discharged from the expanding means 30 is branched into N,and flowed into the evaporator 40 through the independent N refrigerantpassages.

The evaporator 40 functions to receive and evaporate the refrigerantdischarged from the expanding means 30 and then introduce it into thecompressor 10. As shown in the drawing, the evaporator 40 includes afirst evaporating part 41 for receiving and evaporating the refrigerantdischarged from the first discharging part 32 a to an Nth evaporatingpart 4N for receiving and evaporating the refrigerant discharged fromthe Nth discharging part 32 n. Further, the first to Nth evaporatingparts 41 to 4N are arranged in parallel so as to be overlapped in an airflow direction, and thus the air sent by a single blower is passedthrough in turn the first evaporating part 41 to the Nth evaporatingpart 4N so as to be cooled. Of cause, since the first evaporating part41 to the Nth evaporating part 4N are disposed in parallel, therefrigerant passage connecting the first discharging part 32 a and thefirst evaporating 41 and the refrigerant passage connecting the Nthdischarging part 32 n and the Nth evaporating part 4N are also disposedin parallel.

According to the present invention, the evaporating parts 41 to 4Nreceive simultaneously the refrigerant branched and discharged from thedischarging parts 32 a to 32 n. In other words, it means that therefrigerant branched in the expanding means 30 is not supplied in turnto each evaporating part, but supplied at the same time to theevaporating parts 41 to 4N. In the present invention, the refrigerant issupplied to all of the N evaporating parts 41 to 4N so as to exchangeheat with the air blown by the blower 60.

As described above, the N evaporating parts 41 to 4N are disposed inparallel, and the air blown by the single blower 60 is passed through inturn the evaporating parts 41 to 4N. Thus, the air that is primarilycooled in the first evaporating part 41 is flowed into the secondevaporating part 42, and the air that is secondly cooled in the secondevaporating part 42 is flowed into the third evaporating part 43, . . .. This process is repeated N times, and thus the air is repeatedlycooled Nthly.

Herein, the repeated cooling process shows a different aspect from thatin the evaporator arranged in two or more rows. In case of theevaporator arranged in two or more rows, as shown in FIG. 1, therefrigerant is passed through in turn the first and second rows. Therefrigerant absorbs heat from the air while passing through the firstrow, and thus the refrigerant passing through the second row has highertemperature than the refrigerant passing through the first row.Therefore, air cooling performance at the first row is lower than thatat the second row. However, in the present invention, the refrigerantflowed into the evaporating parts 41 to 4N is previously branched into Nfrom the expanding means 30, and thus all the refrigerant flowed intoeach evaporating part 41 to 4N has the same temperature condition. Thatis, in case of a conventional evaporator arranged into multiple rows,the temperature of the refrigerant is increased, (because therefrigerant exchanges heat with the air so as to absorb the heat)whenever passing through each row. Thus, as the row number is increased,the air cooling performance is deteriorated (i.e., in the second rowthan the first row, in the third row than the second row, . . . ).However, according to the present invention, since the temperatureconditions of the refrigerant passing through the evaporating parts 41to 4N are the same as each other, the problem that the air coolingperformance is deteriorated as the row number is increased is basicallysolved. Therefore, the evaporator 40 of the present invention hasexcellent air cooling performance comparing with the conventionalevaporator.

Moreover, since the evaporator 40 is comprised of the evaporating parts41 to 4N arranged in parallel, it is possible to further obtain theeffects as follows. In case of the conventional evaporator shown in FIG.1 or the evaporator shown in FIG. 2B (the two evaporators are disposedin series), the refrigerant passage is long. As the refrigerant passagebecomes long, the heat exchanging performance and the pressure drop rateare increased. However, if the pressure drop rate is excessivelyincreased, it has a harmful effect on the heat exchanging performance.Therefore, in a study on the form enhancement for improving the coolingperformance of the evaporator, it is important to increase the heatexchanging performance and also reduce the pressure drop rate.

In the present invention, the evaporating parts 41 to 4N are disposed inparallel, and the refrigerant flowed into the evaporating parts 41 to 4Nis previously branched in the expanding means 30 into N corresponding tothe number of evaporating parts. Thus the refrigerant passage has thesame length as that in a single evaporator. However, in case of thegeneral evaporator shown in FIG. 1, since the refrigerant has to passthrough all of the two rows, the refrigerant passage has a lengthcorresponding to twice of the length of the general evaporator. In caseof the evaporator shown in FIG. 2B, a length of refrigerant passagebecomes longer. That is, the evaporator 40 of the present inventionminimizes the length of the refrigerant passage so as to remarkablyreduce the pressure drop rate of the refrigerant, thereby maximizing thecooling performance in the evaporator 40.

As the evaporating parts 41 to 4N are disposed at a more upstream sideof a flow direction of the air blown by the blower 60, a distributionrate of the refrigerant is increased. In other words, the distributionrate of the refrigerant is set so that an amount of the refrigerantsupplied to the first evaporating part 41 disposed at an uppermoststream side (which is the most adjacent to the blower 60) is larger thanthat supplied to the second evaporating part 42, and an amount of therefrigerant supplied to the second evaporating part 42 is larger thanthat supplied to the third evaporating part 43. In the present inventionas described above, the refrigerant is simultaneously supplied to eachevaporating part 41 to 4N, and the temperature conditions of therefrigerants supplied to each evaporating part is the same as eachother. However, as the air blown by the blower 60 is passed through theevaporating parts 41 to 4N, a speed of the air becomes slow due to airresistance, and also its temperature is increased due to heat exchangewith the refrigerant. That is, the speed of the air passing through thefirst evaporating part 41 is larger that that of the air passing throughthe second evaporating part 42 . . . , and the temperature of the airpassing through the first evaporating part 41 is smaller that that ofthe air passing through the second evaporating part 42 . . . .Accordingly, the heat exchange performance in the first evaporating part41 disposed at the uppermost stream side is the highest, and the heatexchange performance in other evaporating parts becomes lower gradually.Thus, the distribution rate of the refrigerant is set so that a largestamount of refrigerant is supplied to the first evaporating part 41, anda next largest amount of refrigerant is supplied to the secondevaporating part 42, . . . , thereby maximizing the heat exchangeperformance. In other words, as the evaporating parts are disposed at amore downstream side of the air flow direction, the distribution rate isreduced.

Hereinafter, it will be described regarding to a case that there are twoevaporating parts, i.e., the evaporator includes the first and secondevaporating parts. FIG. 8 is a view showing a p-h line in a conventionalvehicle air conditioner system having a single evaporator and a vehicleair conditioner system having two evaporating regions according to thepresent invention. In FIG. 8, a region #1 is an evaporation region whichis disposed at an upstream side of the air flow generated by the blower60, and a region #2 is an evaporation region which is disposed at adownstream side thereof.

Herein, in case of the present invention, the refrigerant is properlydistributed and supplied according to inlet air temperature (thermalload) for each region. Since the inlet air temperature of the region #1is higher than that of the region #2, a refrigerant flow rate of theregion #1 is larger that that of the region #2.

If a total refrigerant flow rate of the regions #1 and #2 is the same asthat in the conventional evaporator, a refrigerant flow rate passingthrough each evaporating part is smaller than a total refrigerant flowrate passing through the conventional evaporator, because therefrigerant is simultaneously supplied to the multiple evaporating partsthat are parallelly arranged in the air flow direction. Thus arefrigerant pressure loss generated while the refrigerant passes throughan inner portion of the evaporator is reduced. In other words, since therefrigerant is simultaneously supplied to each evaporating part, therefrigerant pressure loss is reduced when passing through eachevaporating part. Owing to the low pressure loss in the evaporator, aninlet pressure of the evaporator is reduced, such that the refrigerantis smoothly expanded and evaporated. Particularly, in case of the region#2, since the flow rate is small, and thus the pressure loss is reduced,pressure of the evaporator is remarkably decreased (also the refrigeranttemperature is also decreased), and the refrigerant is smoothlyevaporated.

Therefore, if the refrigerant is branched and supplied, the inletrefrigerant pressure (temperature) is considerably decreased even in thesame sized evaporator, thereby efficiently evaporating the refrigerant.Herein, the enthalpy difference is the same, but the total refrigerantflow rate is increased, thereby enhancing a heat radiation performanceand thus improving the air conditioner performance.

According to the evaporator 40 of the present invention, since thesingle evaporator 40 is divided into N evaporating regions, it is veryto realize it. For example, in the evaporator shown in FIG. 1, each rowis divided by a partition wall, and each row has an inlet port and anoutlet port. If the evaporator 40 of the present invention is embodiedas described above, the evaporating parts 41 to 4N are disposed to beclosely contacted with each other, and the air passing through oneevaporating part is flowed to the next evaporating part, therebymaximally preventing heat loss and thus maximizing the air coolingperformance. In addition, since the evaporator 40 embodied as describedabove has a shape similar to the conventional evaporator, it is possibleto use a conventional evaporator manufacturing system without additionalinitial investment expense. As a preferable embodiment, in case ofemploying the construction of a general two row heat exchanger, the tworows are completely isolated from each other by using a structure suchas baffle and a partition wall so that the refrigerant is not exchangedbetween the two rows, and inlet and outlet ports are respectively formedat each row, thereby embodying a multi-evaporator of the presentinvention (in this case, the evaporation performs double evaporation).

As described above, the evaporator of the present invention may beconstructed as follows: the single evaporator is divided by thepartition wall so as to form the N evaporating regions, or theevaporating parts 41 to 4N are separately formed to be closed contactedwith each other and arranged in parallel.

FIG. 4 is a view showing an expanding means of the multi-evaporationsystem in accordance with the present invention. As shown in FIG. 4, theexpanding means 30 includes an inlet passage 33 which is connected withan inlet port 31, N outlet passages which are respectively connectedwith N outlet ports 32 a to 32 n, and expanding parts 35, 35 a to 35 nwhich are provided at each passage.

The inlet passage 33 passes the refrigerant introduced from the inletport 31, and the first to Nth outlet passages 34 a to 34 n are formed bybranching the inlet passage 33 into N. The first to Nth outlet passages34 a to 34 n are connected with the first to Nth discharging part 32 ato 32 n so as to discharge the refrigerant.

Hereinafter, the expanding parts 35, 35 a to 35 n having the passageswill be described in detail. Assuming that the expanding part which isdisposed at the inlet passage 33 to throttle the refrigerant is calledan expanding part before branching 35, and the expanding part which isdisposed at the first outlet passage 34 a to throttle the refrigerant iscalled a first expanding part 35 a, . . . and the expanding part whichis disposed at the Nth outlet passage 34 n to throttle the refrigerantis called an Nth expanding part 35 n, the expanding means 30 of thepresent invention includes at least one of the expanding part beforebranching 35, and the first to Nth expanding parts 35 a to 35 n. Forexample, only the expanding part before branching 35 may be provided atthe inlet passage 33, or only the Nth expanding part 35 n may beprovided at the Nth outlet part 34 n, or the expanding part is notprovided at the inlet passage 33 but all the first to Nth expandingparts 35 a to 35N are respectively provided at the first to Nth outletpassages 34 a to 34 n, and the expanding means 30 may be formed intovarious types according to design purpose, desired performance and thelike.

The expanding part before branching 35 and the expanding parts 35 a to35 n may be comprised of one of an expansion valve, an orifice, acapillary tube, and a reducing means.

Further, it is preferable that the expanding means 30 includes theexpanding part before branching 35, and the expanding parts provided atthe outlet passages except the first outlet passage 34 a supplying therefrigerant to the first evaporating part 41 which is disposed at theuppermost stream side of the flow direction of the air blown by theblower 60.

According to the description of the evaporator 40, since the heatexchange performance is the highest in the first evaporating part 41disposed at the uppermost stream side that is the most adjacent to theblower 60, the refrigerant distribution rate supplied to eachevaporating part is set to be gradually reduced from the firstevaporating part 41 toward the Nth evaporating part 4N, i.e., to be thelargest in the first evaporating part 41 and the smallest in the Nthevaporating part 4N. In this case, according to the distribution ratesupplied to each evaporating part 41 to 4N, an amount of the refrigerantpassing through the first outlet passage 34 a becomes maximum, and anamount of the refrigerant passing through the Nth outlet passage 34 nbecomes minimum. Meanwhile, the expanding part before branching 35 isprovided so that the refrigerant is throttled while being passed throughthe expanding part before branching 35, and also since the expandingparts are provided at the outlet passages, the expanded refrigerant isthrottled once more by the expanding parts while being passed throughthe expanding parts 34 a to 34 n, thereby increasing the evaporationefficiency.

Herein, it is possible to obtain an effect of the increase in theevaporation efficiency by the pressure reduction due to the throttlingof the refrigerant, however, there is also possibility of deterioratingthe efficiency due to the pressure drop. In case that the amount of therefrigerant distributed to the first evaporating part 41 becomes thelargest, the amount of the refrigerant passing through the first outletpassage 34 a also becomes maximum. At this time, since the flow rate ofthe refrigerant passing through the outlet passages 34 b to 34 n exceptthe first outlet passage 34 a is relatively small, bad influence due tothe pressure drop is relatively small, and the effect of the increase inthe evaporation efficiency due to the pressure reduction is larger thanthe bad influence. However, in the first outlet passage 34 a, if a largeamount of the refrigerant passing through the first outlet passage isthrottled once more, the refrigerant flow rate is reduced, therebyreducing the efficiency.

Therefore, it is more preferable that the expanding part is provided atthe rest of the passages (the inlet passage, the second outlet passage,. . . , Nth outlet passage) except the first outlet passage 34 a.Because a relatively small flow rate is flowed in the rest of thepassages, the bad influence due to the pressure drop is minimized whenthe expanding parts are additionally provided, and the effect of theincrease in the efficiency is maximized by the pressure reduction due tothe throttling of the refrigerant.

FIG. 7A shows an embodiment of the expanding means 30 which includes theexpanding part before branching 35 and the expanding parts provided atthe outlet passages except the first outlet passage 34 a through whichthe refrigerant is supplied to the first evaporating part 41 disposed atthe uppermost stream side of the flow direction of the air blown fromthe blower 60. In this case, the expanding part before branching 35 isan expansion valve, and the expanding parts provided at the passagesexcept the first outlet passage 34 a may be comprised of a reducingmeans such as an orifice, a capillary tube, and a pipe of which adiameter is reduced in a refrigerant flow direction. Further, in case ofthree or more evaporating parts, the expanding part may be provided atall of the outlet passages except the first outlet passage 34 a, orprovided at parts of the outlet passages except the first outlet passage34 a.

FIGS. 7B and 7C show an embodiment in which the two evaporating partsare provided, wherein the expanding means 30 includes the expanding partbefore branching 35 and the second expanding part 35 b (i.e., which issimilar to the embodiment of FIG. 7A that the expanding part is notprovided at the first outlet passage 34 a, but provided at the inletpassage 33 and the rest of the outlet passages). Herein, FIG. 7B shows acase that all of the expanding part before branching 35 and the secondexpanding part 35 b are the expansion valves, and FIG. 7C (that issimilar to FIG. 7A) shows a case that the expanding part beforebranching 35 is the expansion valve, and the second expanding part 35 bis the reducing means.

FIG. 7D shows an embodiment in which the two evaporating parts areprovided, wherein the expanding part is not provided at the inletpassage 33 (i.e., the expanding part before branching 35 is notprovided), and each expanding part is provided at each outlet passage.In FIG. 7D, there are provided two evaporating parts, and this may beapplied to the multi-evaporation system. In the embodiment, theexpanding means 30 includes the expanding parts 35 a to 35 n which arerespectively disposed at the outlet passages 34 a to 34 n so as tothrottle the refrigerant. The expanding part 35 a to 35 n is formed sothat a pressure reduction level is controlled by adjusting an openingdegree thereof. The expanding means 30 is formed so that a pressurereduction value of the refrigerant supplied to the evaporating partdisposed at the downstream of the flow direction of the air blown by theblower 60 is larger than that of the refrigerant supplied to theevaporating part disposed at the upstream of the flow direction.

The construction of the expanding means 30 is not limited to thedescriptions as described above and the present invention of FIG. 7.

The expanding means 30 may be formed so that the pressure reductionvalue of the refrigerant supplied to the evaporating part disposed atthe upstream of the flow direction of the air blown by the blower 60 islarger than that of the refrigerant supplied to the evaporating partdisposed at the downstream of the flow direction. FIGS. 7A, 7B and 7Care examples of the expanding means which satisfy the conditionsdescribed above. In FIG. 7D, the conditions may be satisfied bycontrolling the opening degree of the first and second expanding parts35 a and 35 b. All constructions which can satisfy the above-mentionedconditions are included in the scope of the present invention, althoughthey are not shown in FIG. 7.

The expanding means 30 may be formed so that the pressure reductionvalue of the refrigerant supplied to the evaporating part in which arelatively small flow rate is supplied is larger than that of therefrigerant supplied to the evaporating part in which a relativelylarger flow rate is supplied. According to the above description of theevaporator and the evaporating part, as the amount of refrigerantsupplied to the more upstream side of the flow direction of the airblown from the blower becomes larger, it is further advantage in theperformance thereof. That is, in case that the distribution rate of therefrigerant supplied to the evaporating part disposed at the moreupstream side becomes larger, the conditions is satisfied by theconstruction of the embodiment of FIG. 7. Of course, the constructionswhich can satisfy the above-mentioned conditions are included in thescope of the present invention, although they are not shown in FIG. 7.

Further detailed description will be described with reference to FIGS. 8and 9. FIG. 8 is a view showing a p-h line in a refrigerating cycledevice having a conventional evaporator and an evaporator of the presentinvention which is divided into two evaporating parts, and FIG. 9 is aview showing a pressure drop rate in the refrigerating cycle device. InFIG. 8, a point A is an inlet port of a compressor, a point B is anoutlet port of the compressor, a point C is an outlet port of acondenser, a point D is an inlet port of a conventional evaporator, apoint D_(#1) is an inlet port of a region #1 in an evaporator of thepresent invention, a point D_(#2) is an inlet port of a region #2 in theevaporator of the present invention, and a point E is an outlet port ofthe evaporator.

In case of an evaporating part (the region #2) which is disposed at thedownstream of the flow direction of the air blown by the blower, since aflow rate of the refrigerant is smaller than that of the refrigerantsupplied to an evaporating part (region #1) disposed at an upstream sideof the air flow blown by the blower, a pressure loss in the evaporatingpart becomes smaller. Therefore, if an additional reducing means 35 b isprovided at a refrigerant passage connected to the region #2 so as toreduce pressure of the refrigerant, it is possible to enhance theevaporation of the refrigerant in the evaporating part.

According to the present invention, it is also possible to enhance theevaporation of the refrigerant by reducing the pressure of therefrigerant (the pressure of the inlet port of the evaporator) suppliedthrough the expanding means to the evaporator corresponding to decreaseof the pressure loss in the evaporator. In comparing pressure loss ratesof the refrigerant in the evaporator (evaporating part), as shown inFIG. 9, ΔP_(conventional type)(pressure drop rate in the conventionalevaporator)>ΔP_(#1)>ΔP_(#2), it can be understood that, as therefrigerant pressure at an inlet port of each evaporating part becomeslower than that at the conventional type, the refrigerant evaporationoccurs more smoothly.

Further, in case of the evaporator of the present invention, since eachevaporating region is disposed in parallel, a total pressure drop rateoccurred in the evaporator is not a sum of the pressure drop ratesoccurred in each region, but depends on the largest pressure loss valueoccurred in the regions. Thus, it is possible to further increase theimprovement effect of the pressure loss.

FIG. 5 shows an embodiment in which a multi-evaporation system of thepresent invention has an ejector. In this case, an ejector 50 is furtherprovided between the evaporator 40 and the compressor 10 so as to mixthe refrigerant discharged from the evaporator 40 and thus improve theconditions such as pressure and temperature.

Detailedly speaking, each refrigerant passing through the evaporatingparts 41 to 4N has a different pressure and temperature condition fromeach other. If the branched passages are combined into one, the mixingis naturally occurred and thus the conditions such as the pressure andtemperature will be equalized. However, the refrigerant may be notcompletely mixed before being supplied to the compressor 10, and thusthe efficiency in the compressor 10 may be partially reduced. In theembodiment of FIG. 5, in order to avoid the problem, the ejector 50 isprovided between the evaporator 40 and the compressor 10.

By using a flow speed of the refrigerant discharged from a part of thefirst to Nth evaporating parts 41 to 4N, the ejector 50 sucks therefrigerant discharged from a part or whole of the rest of theevaporating parts, raises the pressure of the refrigerant and thensupplies the refrigerant to the compressor 10. FIG. 6 shows anembodiment of the ejector according to the present invention. As shownin FIG. 6, the ejector 50 includes a nozzle part 51 which decompressesand expands the refrigerant discharged from a part of the first to Nthevaporating parts 41 to 4N and also increases a flow speed of therefrigerant, a suction part 52 which sucks the refrigerant dischargedfrom part or whole of the rest of the evaporating parts using anincreased flow speed of the refrigerant injected from the nozzle part51, a diffuser part 53 which mixes the refrigerant injected from thenozzle part 51 and the refrigerant sucked through the suction part 52and then raise pressure of the mixed refrigerant. In other words, therefrigerant discharged from a part of the evaporating parts 41 to 4N isflowed into the nozzle part 51 of the ejector 50, and the refrigerantdischarged from the rest is flowed into the suction part 52 of theejector, and then the refrigerants is mixed in the diffuser part 53 ofthe ejector 50. At this time, the refrigerants discharged from theevaporating parts 41 to 4N may be adapted to pass through the ejector50, or a part of the refrigerants may be adapted to be naturally mixedwithout passing through the ejector 50.

The ejector 50 is formed so that the refrigerant has a subsonic speed.Most of the generator ejectors are formed so that the refrigerantpassing through the ejector has a supersonic speed. In this case, anoise generated from the ejector is very large. Since the evaporationsystem of the present invention is installed in a vehicle, it isnecessary to restrain the generation of the noise. Therefore, in thepresent invention, the refrigerant in the ejector 50 has a subsonicspeed instead of a supersonic speed. Accordingly, the ejector 50efficiently mixes the refrigerants without generation of the noise.

The present application contains subject matter related to Korean PatentApplication No. 10-2009-0042057, filed in the Korean IntellectualProperty Office on May 14, 2009 Korean Patent Application No.10-2009-0119621, filed in the Korean Intellectual Property Office onDec. 4, 2009, Korean Patent Application No. 10-2009-0119628, filed inthe Korean Intellectual Property Office on Dec. 4, 2009 and KoreanPatent Application No. 10-2009-0119633, filed in the Korean IntellectualProperty Office on Dec. 4, 2009 the entire contents of which isincorporated herein by references.

While the present invention has been described with respect to thespecific embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

INDUSTRIAL APPLICABILITY

According to the present invention, since the refrigerants passingthrough the evaporating parts 41 to 4N are passed through the ejector 50so as to be smoothly mixed with each other, it is possible to stabilizethe pressure and temperature of the refrigerant flowed into thecompressor 10.

1. A multi-evaporation system, comprising: a compressor 10 which sucksand compresses refrigerant; a condenser 20 which condenses therefrigerant compressed in the compressor 10; an expanding means 30 whichreceives the refrigerant condensed in the condenser 20 through an inletport 31, branches the refrigerant into at lest two or more, dischargesthe refrigerant through at least two or more discharging part 32 a to 32n, and throttles the refrigerant before or after the refrigerant isbranched; and an evaporator 40 which comprises at least two or moreevaporating parts 41 to 4N so as to receive and evaporate therefrigerant discharged from the expanding means 30 and then introducethe evaporated refrigerant into the compressor 10, wherein theevaporating parts 41 to 4N are parallelly disposed in a flow directionof air passing through the evaporating parts 41 to 4N so that the airblown by a single blower 60 is passed through in turn the evaporatingparts 41 to 4N so as to be cooled, and the discharging parts 32 a to 32n and the evaporating parts 41 to 4N are connected by refrigerantpassages disposed in parallel.
 2. The multi-evaporation system of claim1, wherein the refrigerant which is branched and discharged from thedischarging parts 32 a to 32 n of the expanding means 30 is supplied tothe evaporating parts 41 to 4N at the same time.
 3. Themulti-evaporation system of claim 2, wherein a distribution rate of therefrigerant supplied to the evaporating parts 41 to 4N becomes higher asthe evaporating parts 41 to 4N are disposed at a more upstream side ofthe flow direction of the air blown from the blower
 60. 4. Themulti-evaporation system of claim 1, wherein the evaporating parts 41 to4N are formed by dividing the evaporator 40 into at least two or moreevaporating regions.
 5. The multi-evaporation system of claim 1, whereinthe evaporating parts 41 to 4N are formed by dividing the evaporator 40into two evaporating regions.
 6. The multi-evaporation system of claim1, wherein the evaporating parts 41 to 4N are formed separately so as tobe closely contacted with each other and arranged in parallel.
 7. Themulti-evaporation system of claim 1, wherein the expanding means 30comprises: an inlet passage 33 which passes the refrigerant introducedfrom the inlet port 31; and at least two or more outlet passages 34 a to34 n which are formed by dividing the inlet passage 33 into at least twoor more so as to discharge the refrigerant to the discharging part 32 ato 32 n.
 8. The multi-evaporation system of claim 7, wherein theexpanding means 30 comprises an expanding part before branching 35 whichis provided at the inlet passage 33 so as to throttle the refrigerant,and an expanding part 35 a to 35 n which is provided at the outletpassage 34 a to 34 n so as to throttle the refrigerant.
 9. Themulti-evaporation system of claim 8, wherein the expanding part beforebranching 35 and the expanding part 35 a to 35 n are respectivelycomprised of one selected from an expansion valve, an orifice, acapillary tube, and a reducing means.
 10. The multi-evaporation systemof claim 8, wherein the expanding means 30 comprises the expanding partbefore branching 35, and the expanding parts provided at the outletpassages except the first outlet passage 34 a which supplies therefrigerant to the first evaporating part 41 disposed at an uppermoststream side of the flow direction of the air blown by the blower
 60. 11.The multi-evaporation system of claim 10, wherein the expanding partbefore branching 35 is comprised of an expansion valve, and theexpanding parts provided at the outlet passages except the first outletpassage 34 a is comprised of one selected from reducing means comprisingan orifice and a capillary tube.
 12. The multi-evaporation system ofclaim 7, wherein the expanding means 30 is formed so that a pressurereduction value of the refrigerant supplied to the evaporating partdisposed at the downstream of the flow direction of the air blown by theblower 60 is larger than that of the refrigerant supplied to theevaporating part disposed at the upstream of the air flow direction. 13.The multi-evaporation system of claim 7, wherein the expanding means 30is formed so that a pressure reduction value of the refrigerant suppliedto the evaporating part having a relatively small flow rate becomeslarger.
 14. The multi-evaporation system of claim 7, wherein theexpanding means 30 is comprised of expanding parts 35 a to 35 n whichare provided at the outlet passages 34 a to 34 n so as to throttle therefrigerant, and the expanding parts 35 a to 35 n are formed so that apressure reduction level is controlled by adjusting an opening degreethereof.
 15. The multi-evaporation system of claim 14, wherein theexpanding means 30 is formed so that a pressure reduction value of therefrigerant supplied to the evaporating part disposed at the downstreamof the flow direction of the air blown by the blower 60 is larger thanthat of the refrigerant supplied to the evaporating part disposed at theupstream of the air flow direction.
 16. The multi-evaporation system ofclaim 1, further comprising an ejector 50 which is provided between theevaporator 40 and the compressor 10 so as to suck the refrigerantdischarged from a part or whole of the remaining evaporating parts usinga flow speed of the refrigerant discharged from a part of the first toNth evaporating parts 41 to 4N, raise pressure of the refrigerant andthen supply the refrigerant to the compressor
 10. 17. Themulti-evaporation system of claim 16, wherein the ejector 50 comprises:a nozzle part 51 which decompresses and expands the refrigerantdischarged from a part of the first to Nth evaporating parts 41 to 4N,and increases a flow speed of the refrigerant; a suction part 52 whichsucks the refrigerant discharged from part or whole of the remainingevaporating parts using an increased flow speed of the refrigerantinjected from the nozzle part 51; and a diffuser part 53 which mixes therefrigerant injected from the nozzle part 51 and the refrigerant suckedthrough the suction part 52 and then raise pressure of the mixedrefrigerant.
 18. The multi-evaporation system of claim 16, wherein theejector 50 is formed so that the refrigerant has a subsonic speed. 19.The multi-evaporation system of claim 1, further comprises a detectingmeans 70 which is provided at passages for connecting the expandingmeans 30, the evaporator 40 and the compressor 10 so as to detecttemperature and pressure of the refrigerant and control an operation ofthe expanding means 30.